The charted channel depth at Eastport, ME,...

Question 1 of 2707066636eea28f7522a1c51af58

The charted channel depth at Eastport, ME, is 28 feet. You are drawing 31.5 feet and wish 2 feet clearance under the keel. What is the earliest time after 1700 (ZD +4) on 6 September 1983 that you can enter the channel?

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Question 1 of 27070

🔍 Key Concepts

• Chart datum and soundings (charted depth is usually at Mean Low Water) • Required clearance: combine vessel draft and desired under-keel clearance to get minimum total depth needed • Tide tables for Eastport, ME on 6 September 1983 and how to find water height at specific times

💭 Think About

• How do you convert the vessel’s draft and desired under-keel clearance into a minimum water depth you must have? • Given the charted depth, how much tide height above datum is needed to safely enter? • Looking at the tide table for Eastport on 6 Sept 1983, during the period after 1700, when does the predicted tide height first become equal to or greater than that required height?

✅ Before You Answer

• Compute minimum depth = draft + desired clearance (in feet) before you look at the choices • Compute required tide height = minimum depth − charted depth (in feet) and keep that number in mind • Use the tide curve or table values for the evening tide on 6 Sept 1983 at Eastport to find the first time after 1700 when the tide height is at least that required value, then match that time to the closest choice.